Monitoring is a key component of a species conservation program. Well-designed monitoring provides information on species, status, trend, and response to threats and management actions. The BLM has been coordinating and partnering with UDWR in our monitoring efforts for non-game mammals. Through this monitoring program we have had great success defending against Endangered Species Act petitions with systematic inventory and monitoring approaches. American pika, white-tailed prairie dog, Gunnison's prairie dog, wolverine, and pygmy rabbit have all been found to be not-warranted based on monitoring data. Although these species have received not warranted findings in the past, it is essential to conduct periodic monitoring to keep a pulse on populations, demonstrate active management, and be alert to emerging threats. Additionally, we know from many past examples that through litigation, listing findings are often remanded and species are repeatedly petitioned. Much like a routine visit to the doctor- monitoring is needed to diagnose and treat issues before they become unmanageable. We propose to study pygmy rabbits for FY19/20 in partnership with UDWR. This species has not been monitored in northern Utah in over five years. A recent site visit to all known existing and historic locations in the Ibapah area showed no current occupancy. Pygmy rabbits are habitat specialists living only in areas of tall, dense sagebrush with loose soils appropriate for digging burrows (Green and Flinders 1980) and are threatened by the loss and/or deterioration of sagebrush habitats. The rabbits face the same threats faced by the more high-profile greater sage grouse, but with more specialized habitat requirements within a smaller range. The pygmy rabbit was petitioned for Federal ESA listing in 2003 and was found not-warranted in 2010. The petition cited overgrazing, fire, vegetation manipulation, energy development, OHV use, and agricultural and urban development as threats facing the species (Fite et al. 2003). Climate change has been identified as a long-term stressor (Larrucea and Brussard 2008). Recent research from Wyoming found pygmy rabbits may experience declines at even lower levels of landscape disturbance than sage grouse (Germaine et al. 2017). Given continued and emerging threats, an assessment of pygmy rabbit populations within the Salt Lake Field Office is well past due.

The objectives of this study include: 1. Determine occupancy within Box Elder, Ibapah, and Rich County 2. Revisit historic pygmy rabbit sites and habitat treatments to determine occupancy as it relates to recommended habitat treatment buffers 3. Provide data to aid in the development of a species distribution model 4. Identify areas that may benefit from juniper removal and improve pygmy rabbit habitat

The pygmy rabbit was petitioned for Federal ESA listing in 2003 and was found not-warranted in 2010. The petition cited overgrazing, fire, vegetation manipulation, energy development, OHV use, and agricultural and urban development as threats facing the species (Fite et al. 2003). Climate change has been identified as a long-term stressor (Larrucea and Brussard 2008). Recent research from Wyoming found pygmy rabbits may experience declines at even lower levels of landscape disturbance than sage grouse (Germaine et al. 2017). Given continued and emerging threats, an assessment of pygmy rabbit populations within the Salt Lake Field Office is well past due.

This project will provide pygmy rabbit occupancy data of populations supporting the need for data in upcoming grazing permit renewals. Additionally, BLM Manual 4680 directs the BLM to "determine, to the extent practicable, the distribution, abundance, population condition, current threats, and habitat needs" for sensitive species. The status of pygmy rabbit populations are currently unknown in the SLFO, additionally historic sites appear to be unoccupied. Data collected in this survey effort will provide data to inform analyses, planning, and implementation in project areas where pygmy rabbits exist. Furthermore, areas may be identified in this effort that would benefit from restoration work such as juniper removal. These data are needed in order to process permit renewals, and land and realty actions quickly. Locations of pygmy rabbit populations and burrows allows biologist to microsite projects and adjust prior to NEPA initiation, thereby reducing paperwork and time required to process requests.

This project will provide pygmy rabbit occupancy data of populations supporting the need for data in upcoming grazing permit renewals. Additionally, BLM Manual 4680 directs the BLM to "determine, to the extent practicable, the distribution, abundance, population condition, current threats, and habitat needs" for sensitive species. The status of pygmy rabbit populations are currently unknown in the SLFO, additionally historic sites appear to be unoccupied. Data collected in this survey effort will provide data to inform analyses, planning, and implementation in project areas where pygmy rabbits exist. Furthermore, areas may be identified in this effort that would benefit from restoration work such as juniper removal. These data are needed in order to process permit renewals, and land and realty actions quickly. Locations of pygmy rabbit populations and burrows allows biologist to microsite projects and adjust prior to NEPA initiation, thereby reducing paperwork and time required to process requests.

Not applicable

This project will provide pygmy rabbit occupancy data of populations supporting the need for data in upcoming grazing permit renewals. Additionally, BLM Manual 4680 directs the BLM to "determine, to the extent practicable, the distribution, abundance, population condition, current threats, and habitat needs" for sensitive species. The status of pygmy rabbit populations are currently unknown in the SLFO, additionally historic sites appear to be unoccupied. Data collected in this survey effort will provide data to inform analyses, planning, and implementation in project areas where pygmy rabbits exist. Furthermore, areas may be identified in this effort that would benefit from restoration work such as juniper removal. These data are needed in order to process permit renewals, and land and realty actions quickly. Locations of pygmy rabbit populations and burrows allows biologist to microsite projects and adjust prior to NEPA initiation, thereby reducing paperwork and time required to process requests.

UDWR will conduct pygmy rabbit surveys and monitoring it the Ibapah, Rich, and Grouse Creek areas.

The SLFO and UDWR will monitor identified pygmy rabbit sites on a project by project basis and during the UDWR survey cycle as identified in the Wildlife Action Plan.

Utah Division of Wildlife Resources Bureau of Land Management Brigham Young University

Develop species distribution model. Use data in species status assessments. Identify areas where juniper removal may benefit pygmy rabbit.

Data will be used to support grazing permit renewals, fuels projects, and aid in pygmy rabbit conservation efforts.

07/01/2020

06/30/2024

2024

This funding supported efforts to investigate the distribution of pygmy rabbits in Box Elder and Rich Counties. It supplemented other funding which took a statewide approach. We built a sampling frame based on models of the 4 core population areas, Rich Co (NRO), Box Elder Co (NRO), West Desert (SRO), and Fishlake (SRO). Random cells (250m x 250m) were sampled by area search and any positives initiated searches of the next nearest cells. Random cells yielded no positive results so were abandoned in favor of resampling all known and historic areas within these population cores. The models were too simplified and overpredictive, and much better refinement is needed for these models to be useful. Prior sampling has been largely effective in finding pygmy rabbits and we are reasonably sure we have a mostly complete knowledge of where pygmy rabbits occur. Area searches consisted of looking for burrows and pellets. Only 2 burrows would be marked and recorded within the grid cell, so the cell may contain other unmarked burrows but would be marked as active at the cell level. Burrows were assessed for use, by presence of pellets (fresh or aged), and level of burrow maintenance (open vs debris or spider web presence), or whether burrows were collapsed. When sign at a burrow was inconclusive about which species was using it, or about activity level, trail cameras were set for at least 4 nights to determine burrow status. All data was entered into a joint database (statewide, and gathers data collected by partnering agencies like BLM) using a Survey123 form. Current or recent sign of pygmy rabbits was recorded at 723 locations.

Project goals were to assess the current status of historically identified pygmy rabbit sites. We also used habitat modeling and surveys to investigate other sagebrush areas an better define distribution. The habitat models were overpredictive and would need to be refined to be useful for management decisions. As such, random sampling based on these models did not identify any rabbit locations (previously known or unknown). Monitoring needs to focus on resampling of known areas to determine persistence through time. New locations were still identified, but not from the models and only by observation while traveling between survey locations. Through searches in historical areas, we were able to confirm persistent pygmy rabbit populations in all four core areas. This is especially important as rabbit hemorrhagic disease was documented in 2021 and there was fear it could extirpate populations. Specifically for Northern Utah, we found robust pygmy rabbit populations in Rich County and Box Elder County. This work confirmed and expanded the known distribution in both areas.

Continued monitoring of known locations will be key to determining population status and persistance. Modeling habitat may be useful but only if they can be more accurate. Management actions and decisions about habitat treatments should consider rabbit occurrence and since models are unreliable, projects with potential rabbit use should be surveyed or treated as if they are present. Data will continue to be collected and next analysis steps are unclear at the moment since our random sampling did not provide needed results to even be analyzed. Data and maps are still useful in directing management actions and responding to concerns about population status. ESMF has funded a graduate student at BYU to more intensively study the long-term response of pygmy rabbits to habitat fragmentation. As nearly all pygmy rabbit habitat in Utah is within Sage Grouse Management Areas, we plan to work within that framework to ensure areas and activities supporting both species are prioritized.